Field of the Invention
The present invention relates to a rechargeable battery with a case including a vent.
Description of the Related Art
With advancement of technology and increasing demand for mobile devices, demand for rechargeable batteries as energy sources has been increasing.
For example, a cylindrical rechargeable battery includes an electrode assembly formed by disposing electrodes at opposite surfaces of a separator and winding the electrodes in a jelly roll form, a case accommodating the electrode assembly, and a cap assembly sealing an opening side of the case.
The cap assembly and an opening of the case interpose a gasket therebetween to be assembled by a crimping process.
That is, the case holds an external circumference of the cap assembly with a clamping portion connected to a beading portion recessed toward a diametrical center of the case from the opening side.
Due to charging and discharge operations of the electrode assembly, gas is generated inside of the rechargeable battery.
The generated gas increases the internal pressure of the rechargeable battery.
When the internal pressure reaches a predetermined value, a vent provided at one side of the case is opened to discharge the gas, thereby potentially preventing explosion of the rechargeable battery.
The case is provided with a plating layer to prevent it from being oxidized.
The case is punched by a punch to be formed with the vent having a predetermined depth.
When the vent is formed with a single punching operation, the plating layer can be damaged as a surface of the vent becomes rough, thereby causing the vent to be oxidized while it is used.
In addition, when the vent is formed by a single strong punching operation, the impact of the punch may shorten a lifespan of the punch.
The above information disclosed in this Background section is only for enhancement of understanding of the background of the invention and therefore it may contain information that does not form the prior art that is already known in this country to a person of ordinary skill in the art.